spr¶
Performs a rank-1 update of a symmetric packed matrix.
Description¶
The spr
routines compute a scalar-vector-vector product and add the
result to a symmetric packed matrix. The operation is defined as
where:
alpha
is scalar,A
is ann
-by-n
symmetric matrix, supplied in packed form,x
is a vector of lengthn
.
API¶
Syntax¶
void spr(queue &exec_queue,
uplo upper_lower,
std::std::int64_t n,
T alpha,
buffer<T,1> &x,
std::int64_t incx,
buffer<T,1> &a)
spr
supports the following precisions and devices.
T |
Devices Supported |
---|---|
|
Host, CPU, and GPU |
|
Host, CPU, and GPU |
Input Parameters¶
- exec_queue
The queue where the routine should be executed.
- upper_lower
Specifies whether
A
is upper or lower triangular. See Data Types for more details.- n
Number of rows and columns of
A
. Must be at least zero.- alpha
Scaling factor for the matrix-vector product.
- x
Buffer holding input vector
x
. The buffer must be of size at least (1 + (n
- 1)*abs(incx
)). See Matrix Storage for more details.- incx
Stride of vector
x
.- a
Buffer holding input matrix
A
. Must have size at least (n
*(n
-n))/2. See Matrix Storage for more details.
Output Parameters¶
- a
Buffer holding the updated upper triangular part of the symmetric matrix
A
ifupper_lower =upper
, or the updated lower triangular part of the symmetric matrixA
ifupper_lower =lower
.